package com.example.performance.jmh.official;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Group;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
import org.openjdk.jmh.runner.options.TimeValue;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;

@SuppressWarnings({"java:S101", "java:S100"})
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Group)
public class JMHSample_30_Interrupts {

    /*
     * JMH can also detect when threads are stuck in the benchmarks,
     * and try to forcefully interrupt the benchmark thread.
     * JMH tries to do that when it is arguably sure it would not affect the measurement.
     */

    /*
     * In this example, we want to measure the simple performance characteristics of the ArrayBlockingQueue.
     * Unfortunately, doing that without a harness support will deadlock one of the threads,
     * because the executions of take/put are not paired perfectly.
     * Fortunately for us, both methods react to interrupts well,
     * and therefore we can rely on JMH to terminate the measurement for us.
     * JMH will notify users about the interrupt actions nevertheless,
     * so users can see if those interrupts affected the measurement.
     * JMH will start issuing interrupts after the default or user-specified timeout had been reached.
     *
     * This is a variant of com.example.performance.jmh.official.JMHSample_18_Control,
     * but without the explicit control objects.
     * This example is suitable for the methods which react to interrupts gracefully.
     */

    private BlockingQueue<Integer> q;

    @Setup
    public void setup() {
        q = new ArrayBlockingQueue<>(1);
    }

    @Group("Q")
    @Benchmark
    public Integer take() throws InterruptedException {
        return q.take();
    }

    @Group("Q")
    @Benchmark
    public void put() throws InterruptedException {
        q.put(42);
    }

    /*
     * ============================== HOW TO RUN THIS TEST: ====================================
     *
     * You can run this test:
     *
     * a) Via the command line:
     *    $ mvn clean install
     *    $ java -jar target/benchmarks.jar JMHSample_30 -t 2 -f 5 -to 10
     *    (we requested 2 threads, 5 forks, and 10 sec timeout)
     *
     * b) Via the Java API:
     *    (see the JMH homepage for possible caveats when running from IDE:
     *      http://openjdk.java.net/projects/code-tools/jmh/)
     */

    public static void main(String[] args) throws RunnerException {
        Options opt = new OptionsBuilder()
                .include(JMHSample_30_Interrupts.class.getSimpleName())
                .threads(2)
                .forks(1)
                .warmupTime(TimeValue.seconds(1))
                .measurementTime(TimeValue.seconds(1))
                .timeout(TimeValue.seconds(1))
                .build();

        new Runner(opt).run();
    }

}
